Mayer noted that after Yahoo discovered the first hacks in late 2016, Yahoo required all of its users to change their passwords if they hadn't, and scrapped old security questions.

Last month, Yahoo reported its entire user base of 3 billion accounts was compromised in an August 2013 data breach. She said "really aggressive" pursuit of hackers was needed to discourage the efforts, and that even the most well-defended companies "could fall victim to these crimes".

A representative for Mayer said on Tuesday she was appearing voluntarily.

The current and former chief executives of credit bureau Equifax, which disclosed in September that a data breach affected as many as 145.5 million US consumers, said they did not know who was responsible for the attack. Roger Wicker, R-Miss., asked all of those testifying, including the interim and former CEOs of Equifax, Paulino de Rego Barros Jr. and Richard Smith, as well as Entrust Datacard CEO Todd Wilkinson, if they took issue with Nelson's contention that a "mere company" can not withstand persistent attacks from state-backed hackers without the help of the National Security Agency.

Mayer joined former and current CEOs of Equifax in testifying before the committee examining recent data breaches.

He also said the company is on schedule to release a computer app in January that will allow consumers to lock and unlock their credit data.

Those remarks prompted Committee Chairman John Thune, R-S.D., to ask Mayer why, despite these investments, Yahoo failed to detect the massive 2013 breach for three years. But she also said the U.S. government has to do more to empower law enforcement to pursue and stop hackers, especially the state-sponsored kind.

Sheep Can Recognize Obama's Face, New Study Shows
Even when a celeb's face was slightly tilted rather than face-on, the sheep still picked the image more often than not. The BBC quoted researchers as stating that "sheep possess similar face recognition abilities to primates".

Turkey, US resume limited mutual visa services
Turkey's embassy in Washington has also said it will process visa applications from United States citizens on a limited basis. Turkey also suspended the issuance of visas to USA citizens, according to Trend.

Bowling Green man charged with assaulting Sen. Paul
Kentucky State Police Master Trooper Jeremy Hodges said he could not release details of the assault because of security issues. Hodges said Boucher would have faced more serious charges if had he used a weapon or if Paul had been injured seriously.

Japan's 'black widow' sentenced to death by hanging
She said her husband treated her unfairly when it came to finances, giving more money to a woman he previously dated than to her. A court-appointed physician said past year that Kakehi's case of dementia was mild and that she was fit to stand trial.